Affiliation:
1. Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York
Abstract
ABSTRACT
Microbial biofilms contribute to virulence and resistance to antibiotics by shielding microbial cells from host defenses and antimicrobial drugs, respectively.
Cryptococcus neoformans
was demonstrated to form biofilms in polystyrene microtiter plates. The numbers of CFU of disaggregated biofilms, 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2
H
-tetrazolium hydroxide reduction, and light and confocal microscopy were used to measure the fungal mass, the metabolic activity, and the appearance of
C. neoformans
biofilms, respectively. Biofilm development by
C. neoformans
followed a standard sequence of events: fungal surface attachment, microcolony formation, and matrix production. The susceptibilities of
C. neoformans
cells of the biofilm and planktonic phenotypes to four antifungal agents were examined. The exposure of
C. neoformans
cells or preformed cryptococcal biofilms to fluconazole or voriconazole did not result in yeast growth inhibition and did not affect the metabolic activities of the biofilms, respectively. In contrast, both
C. neoformans
cells and preformed biofilms were susceptible to amphotericin B and caspofungin. However,
C. neoformans
biofilms were significantly more resistant to amphotericin B and caspofungin than planktonic cells, and their susceptibilities to these drugs were further reduced if cryptococcal cells contained melanin. A spot enzyme-linked immunosorbent assay and light and confocal microscopy were used to investigate how antifungal drugs affected
C. neoformans
biofilm formation. The mechanism by which amphotericin B and caspofungin interfered with
C. neoformans
biofilm formation involved capsular polysaccharide release and adherence. Our results suggest that biofilm formation may diminish the efficacies of some antifungal drugs during cryptococcal infection.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
Cited by
162 articles.
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